Hezonja reminds me of Peja Stojakovic. A top shooter from spot ups and catch and shoots but limited as a ball-handler which limits his value as a scorer in one-on-one situations and in the pick and roll.
I think he is a guy who can get you 17-20ppg at his peak and hopefully play solid defense. As a 2nd or preferably 3rd option, I think he can be really good.
Not a fan of his handles, but I think drawing a comparison between Peja and Hezonja on that regard is off. Hezonja is quite the superior ball handler and more explosive as well, so I wouldn't pigeon-hole him into a spot-up/catch-and-shoot player. Though shooting off the dribble is something to work on.
I don't know he'll end up being as effective as Peja was as its peak, as he was simply deadly when he could get off a shot, but I think his ceiling is quite higher with all the rest he brings to the court plus explosiveness.
I've only seen him in limited instances, but I think his ball handling and playmaking ability is something he as in him at least at a competent level.